Long-term prognostic value of an index of myocardial performance in patients with myocardial infarction

Abstract

Background: The Tei index of myocardial performance (IMP), which combines parameters of both systolic and diastolic ventricular function, is a useful prognostic factor in many clinical settings. Hypothesis: This study assessed the long-term prognostic value of IMP in patients discharged from hospital after acute myocardial infarction (AMI). Methods: Doppler/echocardiographic studies were recorded in 90 consecutive patients on Day 14 ± 2 following an AMI. The IMP was calculated from the Doppler recordings, as a sum of isovolumetric contraction time and isovolumetric relaxation time, divided by the ejection time. Results: The patients were followed for an average (SD) of 57.8 (16.1) months. During this period there were 22 (24%) cardiac events, defined as cardiac deaths (10) or nonfatal recurrent myocardial infarctions (12). After multivariate Cox analysis, Tei index>0.55 (relative risk [RR] 4.45;95% confidence interval [CI] 1.28-15.45;p=0.019), LV end-systolic volume>65 ml (RR 3.23;95% CI 1.34-7.79;p=0.009), and mitral E wave deceleration time≤0.145 s (RR 2.94;95% CI 1.24-6.92;p=0.014) were the only independent predictors of cardiac events during the follow-up period. In a subgroup of patients with preserved LV systolic function (ejection fraction >0.40), IMP was the only predictor of cardiac events (RR 6.37;95% CI 1.32-30.77, p=0.02). Conclusions: The Tei index of myocardial performance, which is simple and easy to calculate, is a useful tool for risk assessment in patients following myocardial infarction, and in a subgroup of patients with normal or only mildly impaired systolic function.